Shutting down AC on floors 1 to 7 likely allows them to get better performance on floors 8 to 13
But I am unconvinced that AC manufacturers have different "sizing"... An AC unit is for hot places and the outdoor unit may be in a very hot spots with ambient easily above 40C.
Edit: Yes, AC systems for a whole building are different but still the system on the roof experiences the full Sun and very hot conditions, this isn't the issue. Perhaps they simply badly designed it so that it hasn't got the capacity to cool the whole building when it's actually hot so they prioritised (actually now I get that this is what you meant). Obviously it is easier to blame "weather conditions"...
Also 19 satellite antennae, if my count is right.
By sizing I simply mean the number and capacity of roof units. Cooling an office building down by 8C is a lot easier than cooling it by 18C. I doubt half the roof units are shut down. Maybe some are, but most will have their output redirected to cooling the top half of the building
Edit: it'd be interesting to know how many buildings in Belgium have had the same issue.
It's like saying what's the point of having a house if you aren't safe in it during a tornado. It's an exceptional event. The problem is that these truly exceptional events which only happened once every 10 days for a day or two, are now becoming a norm. My own 12k BTU minisplit could cool my house down every summer, no problem, even down to 18C if I wanted it to. But in the recent heatwave it just can't keep up, there is more heat coming into the house than the system can remove.
Just like heat pumps for heating in winter are amazing for our regular mild-ish winters, but if you get a really cold spell and it drops to -35C, it's just not going to work at all to a point where it might not even start - you could also say "well what's the point of a heating system that can't heat in extreme cold".
The extreme is the keyword.